The New Year will come with a market share showdown -- a high noon in the U.S. auto marketplace, but with new rules. Certainly not Gary Cooper's High Noon, not even Neo and Trinity's "Guns, lots of guns" rescue in The Matrix.

But a shootout all the same. And the risk-reward ratio is tempting enough to challenge the production-and-incentive discipline automakers have shown since the recovery started in mid-2009.

And loose market share is easier and cheaper to conquest. Stop hand chiseling flakes off granite walls and shovel up the shards the cannonballs knocked off.

Consider the scale of the market share in play. Compare 2007, the last year of the Old Normal, with the first 11 months this year. Then contrast this year to date with the same period a year ago.

The net result: a whole lotta share shakin' going on.

Four of the Big 7 reversed momentum this year. General Motors lost 4.0 share points after 2007 but has recaptured 0.7 of a point this year. Its bankruptcy twin Chrysler Group dropped 3.5 share points from 2007 to 2010, but is up 1.3 points through November. American Honda gained a point between 2007 and last year but is down 1.5 share points since. Ford Motor Co. picked up 1.1 points by 2010, but with just the Ford and Lincoln brands this year has slipped 0.2 points.

And there are stark differences in the three players that have maintained their momentum. Toyota Motor Sales lost a point between 2007 and 2010 and then another 2.5 points this year. But Nissan North America and Hyundai-Kia Automotive are the biggest gainers. Over four years, Nissan grabbed 1.6 share points and the Koreans a staggering 4.2 share points.

Add up the four-year share losses of just four automakers and in a 12.7 million-unit market, that's a swing of more than 1.3 million car buyers.

And that understates what's in play, by Polk analyst Anthony Pratt's count. Don't forget that owners of newly orphaned brands -- Pontiac, Saturn, Mercury, Saab and Hummer -- are unaffiliated the next time they shop. And the under-30s "Peter Pan" generation that supposedly prefer smartphones to cars? Pratt says they simply can't yet afford cars on McJob salaries and are a huge future "at loose" bloc without car-brand preferences.

Let's call these groups the Peter Pan and the Orphans contingent.

Add it all up and there's a lot of unattached singles at the dance.

We'll see a lot of competition for these buyers next year. But in this post-High Noon environment, the gunplay will be silenced. Less cash on the hood and more subvented lease and financing deals. Fewer rebates but more advertising and dealer cash.

But the competition will be fierce. Automakers can't stand pat. Customer loyalty ain't what it used to be.

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